Air miles recorder and follow-up system



June 1952 J. H. ANDRESEN, JR

AIR MILES RECORDER AND FOLLOW-UP SYSTEM Filed March 26, 1946 INVENTOR JOHN HANDRESE/Vjl: BY ,f

@i yw ATT RNEY Patented June 1 7, 1952 UNITED STATES PATENT OFFICE AIR MILES RECORDER AND FOLLOW-UP- SYSTEM John H. Andresen, Jr., Port Washington, N. Y., assi'gnor', by mesne assignments:- to- Kollsman Instrument Corporation, Elmhurst, N. Y., a corporation of New York Application March 26, 1946, Serial No. 657,190

Iii-Claims. 12 This invention relatesspecifically to an aircraft recorder of air miles traveled employin an optical follow up system controlling thespeed of a variable speed motor in responseto theoperationof an airspeed indicator, the recorder integrating airspeed with time to register the air miles traveled.

Generally the invention relates to an optical follow-up system of. general application where it is desired to produce a follower movement in response to. change of position of an: actuated element.

Also generally the invention relates-: t v an air miles recorder'in whichmeans.responsive to a'ir-- speed controls. the. speed of avariabl'e speed motor tointegrate speed with time; regardless; of the specific" formof. the follow-up system used.

An object of the. invention is to provide an optical follow-up systeminvwhichlight rays; are directed upon a light sensitive element through a pair of reflectingimirrors with one of th irrors varying its position and with the second mirror following the position of the first mirror.

to maintain the light rays at the desired point with respect to the light sensitive element,

Another objector the invention is to provide an optical follow-up system in which the light rays are directed upon a light sensitive element in which the light source and sensitive element are stationary and the mirrors movable, withthe: movement of one mirror following the movement of the other mirror to: maintainrthe-direv' tion of the light rays upon the light sensitiveelement.

Another: object of the invention isto provide an optical follow-up system in which light rays are directed to alightsensitive element through a system including a pair of movable: mirrors. with one mirror. movable'in; response to an ex-- ternal condition and with the operation of the follow-up system properly moving; the second:

mirror to follow the movement of the first mirror in accordance with: variation in the: exterior condition.

Another object of. the inventio'mis. to provide;

an aircraft air miles recorder utilizing a follow up system in accordance with'th'e precedingi 011 jects with the firster operated mirror moved by an airspeed indicator.

Another object ofthe invention is toprovide an aircraft-air miles recorder in accordance with the preceding objects'in which the movement of" the follower mirror is responsive tothe speedof rotation of a variablespe'ed motor connected to a counter indicating the mileagetraveled.

Another object of the invention is the provision of an aircraft air miles recorder in which means responsive to airspeed controls the" speed of IOtELlSlOn of a variable speed motor connected to a counter for registering: air miles traveled.

Another object of the invention is the pr0- vision of an aircraft air miles recorder having a first element movable in responseto the-operation of an airspeed indicator and a second element cooperable therewith to follow the mOVement thereof with the position of the second element" controlled by the speed of rotation of avariable spe'edrnotor connected to a counter registering air miles traveled, the speed of rota-' tion of the motor being controlled in accordance with the position of the first element;

Other objects and features of" theinvention will be readily apparent to those skilled in the art from thespecification and appended draw i 's illustrating certain preferred embodiments in which:

Figure 1 is aschematic representation of the air miles recorder according tethe presentinvention employing the novel form of optical follow-up system.

Figures is-a schematic wiringdiagram of the recorder and system;

As. specifically illustrated inthe drawing; the combined arrangement includes a light source I, the light rays from which are collimated by a lens 2- and directed toa mirror 3 from which y are reflected to a second mirror 4- and thence to a lens- 5' focusing the rays upona photoelectric cell unit 6. In front of the light sensitive" photoelectric cell unit 6 is disposed" a shield 1 impervious to light and providing a light my cut-off point indicated at 8.

The mirror" 3"; which is the-operating mirror" of the follow-up system, is mounted upon" the shaft 9 of a true airspeed indicator' ll of conventional form having pressure connection l2 and static connection t3 toan aircraft Pitot static tube and a thermometer connection M. This true airspeed indicator is of well known construction and for the ordinary staff and pointer there has been substituted the shaft ii which carries the mirror" 3.

'I'he'follo'we mirror 4' is mounted upone shaft I5 upon which is mounted the drag cup 16" of a dragcup tachometer indicated at I1. The drag cuptachomet'er includes'perma'nent magnet ele ments [8- driven by a variable speed motor It;

The shaft! 5 of the drag cup tachometer'is biased against rctation by'a spring 21' and; in accordancewith the well known principles of such tachometers, the arc of rotation of the shaf l5 will be determined by the speed of rotation of the motor is and the magnetic elements i3 driven thereby. The motor 19 also drives a system of reducing gears indicated at 22 and corn nected through gear wheels 23 and 24 to a counter or register indicatin the miles traveled In the schematic representation of the wiring diagram for the system illustrated in Figure 2, there is shown an alternating current source indicated by the lines and 27. Ehe line 21' is connected to the anode of the photoelectric unit the cathode of which is connected to the control grid 28 of an electronic tube 29. Across th supply wires 25 and El is disposed a voltage dividing resistor and connected to point thereon toward the line 23 side of the mid point are the cathode 32 and suppressor grid oi the electpnic tube 23. resistor 34 is connected between the grid 23 and the line 26. There is provided a reversible motor indicated at 35 energized by a two phase winding one of which is shown at the other at 3?, the winding 33 being fed through a condenser and the winding 3'1 through a condenser 35. The anode 4! of the tube 23 is connected to bypass the condenser 38.

The operation of the motor reversing circuit is described and claimed in applicants co-pending application Serial No. 644,136 filed January 29, 1946, which matured into Patent No. 2,437,064, March 2, 1948, entitled Motor Control. When the tube 29 is not firing, the motor 35 operates in a direction determined by the values of the condensers 33 and 39, the condenser 39 having a greater capacity so that the current in the winding 33 leads that in the winding 31. When, however, the tube 29 is firing, it provides a substantially resistive circuit feeding the winding 33 so that the current in winding 36 will follow that in the winding 3? while the tube is conducting to reverse the direction of the motor 35.

The motor is connected through a suitable mechanical connection indicated by the dotted line 42 to a variable rheostat 43 connected in series with one of the two phase windings 44 of the motor 19, the other winding 45 of which is fed through condenser 46. The speed of rotation of the motor 19 is thus determined by the position of the rheostat 43 which is in turn controlled by the motor 35 which rotates in opposite directions to increase or decrease the resistive value of the rheostat.

With the elements of the optical system, in-

cluding the cut-off point 8 of the photoelectric cell, all at the same level, the mirrors 3 and 4 will be parallel when the image of the light source 1 is at the cut-off point 8 and a linear follow-up response will be obtained. These posi- J tions may, of course, be varied as desired within the contemplation of the invention to secure any desired responsive relation.

In the operation of the system let it be assumed that the mirrors 3 and 4 are in parallel relation or in what other predetermined relation corre: sponds to the light image at the cut-off point 8. Should the airspeed of the aircraft change, the shaft 3 will be rotated to rotate the mirror 3. This will move the image of the light source either into the zone where it is cut oii by the shield l or into the zone where it is directed upon the photoelectric unit 6. When the image of the light source is cut ofi by the shield '1, the tube 29 will not fire and the motor 35 will rotate A grid bias in a first direction to vary the resistance of the rheostat 43 in a first direction. This will change the speed of the motor [9 in a first direction and the change in speed of the motor l9 will be accompanied by a rotation of the shaft [5 of the drag cup tachometer IT to rotate the mirror 4 into parallelism or otherpredetermined arrangement with the mirror 3.

When the image of the light source is directed upon the photoelectric unit 6, the tube 29 fires so that the motor 35 reverses its direction of rotation as previously described to drive the rheostat 43 in the reverse direction which in turn changes the speed of the motor 19 in the reverse direction. This again changes the response of the drag cup tachometer I! to return the mirror 4 into parallelism with the mirror 3. In the operation of the follow-up system the motor 35 will be continually hunting or rotating in opposite directions to maintain the light ray image at the cut-off point 8 of the photoelectric cell.

Since the speed of rotation of the motor I8 is a function of the response of the true airspeed indicator l l, the number of revolutions of the motor l9 as indicated on the counter 25 integrates the variables speed and time to provide a direct reading on the counter 25 of air miles traveled.

It will, of course, be understood that the optical follow-up system herein specifically disclosed with the air miles recorder is of general application where any follow-up of a movable element is desired.

It will also be understood that while the air miles recorder herein specifically disclosed is utilizing an optical follow-up system, it may incorporate other follow-up systems such as pneumatic, mechanical or electrical; for example that disclosed in the aforesaid application Serial No. 644,136 now Patent No. 2,437,064.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims.

What is claimed is:

1. In an air miles recorder for aircraft, means responsive to airspeed, a first element movable by said airspeed responsive means, a variable speed motor, means responsive to the speed of rotation of said variable speed motor, a second element movable into predetermined relation with said first element by said means responsive to the speed of rotation of said variable speed motor, means controlled by the position of said elements relative to each other for controlling the speed of rotation of said variable speed motor, and indicating means responsive to the revolutions of said variable speed motor for registering the air miles traveled.

2. In an air miles recorder for aircraft, means responsive to airspeed, a first element movable by said airspeed responsive means, a variable speed motor, means responsive to the speed of rotation of said variable speed motor, a second element movable into predetermined relation with said first element by said means responsive to the speed of rotation of said variable speed motor, a reversible motor whose direction of rotation is controlled by the position of said elements relative to each other, means for controlling the speed of said variable speed motor in response to rotation of said reversible motor, and air miles indicating means. driven by said variable speed motor.

3. In an air miles recorder for aircraft, means responsive to airspeed, a first element whose. position is determined by said airspeed responsive.

means, a variable speed motor, means responsive to the speed of rotation of said variable speed motor, a second element whose position is determined by said means. responsive to the speed of rotation of said variable speed motor, speed control means for said variable speed motor, means controlled by the positioning of saidelements relative to each other for operating said speed control means to vary. the speed of said motor, and air miles indicating means driven by said motor.

4. In an air miles recorder for aircraft, means responsive to airspeed, a, first element whose posi-' tion is determined by said airspeed responsive means, a variable speed motor, means responsive to the speed of rotation of said variable speed.

motor, a second element whose position is determined by said means responsive to the speed of rotation of said variable speed motor, speed control means for said variable speed motor, means controlled by the positioning of said elements relative to each other for operating said speed control means to vary the speed of said motor, and means responsive to the revolutions of said motor to integrate speed with time to indicate the air miles traveled.

5. In an air miles recorder for aircraft, means responsive to airspeed, a first element whose position is determined by said airspeed responsive means, a, variable speed motor, means responsive to the speed of rotation of said variable speed motor, a second element whose position is determined by said means responsive to the speed of rotation of said variable speed motor, a reversible motor whose direction of rotation is determined by the position of said elements relative to each other, speed control means for said variable speed motor operated by said reversible motor, and a register driven by said variable speed motor for recording the air miles traveled.

6. In an air miles recorder for aircraft, means responsive to air speed, a first element movable by said means responsive to air speed, a variable speed motor, a drag cup tachometer driven by said variable speed motor, a second element movable by said drag cup tachometer, means responsive to the relative position of said elements for controlling the speed of said motor, and means responsive to the revolutions of said motor for recording the air miles traveled.

'7. In an air miles recorder for aircraft, means responsive to air speed, a first element movable by said means responsive to air speed, a variable speed motor, a drag cup tachometer driven by said variable speed motor, a second element movable by said drag cup tachometer, speed control means for said variable speed motor, a reversible motor driving said speed control means, means responsive to the relative position of said elements for controlling the direction of rotation of said reversible motor, and means responsive to the revolutions of said variable speed motor for recording the air miles traveled.

8. In an air miles recorder for aircraft, means responsive to airspeed, a variable speed motor, an optical follow-up system including a light source, a light sensitive element and an optical system containing means including a pair of mirrors for directin the light rays from said light source upon the light sensitive element, means for positioning one of said mirrors by said airspeed re sponsive. means, means for positioning the, other of said mirrors; by the speed of rotation of said variable speed motor, means employing said light source, mirrors and light sensitive elements for controlling the speed of said variable speed motor in response to the position of said light rays relative to the light sensitive element, and means responsive to the revolutions of said variablev speed motor for recording the air miles traveled.

9. In an air miles recorder for aircraft, means responsive to airspeed, a variable speed motor, an optical follow-up system including a light source, a light sensitive element, and an optical system r containing means including a pair of mirrors for directing the light rays from said lightsource upon the light sensitive element, means for positioning one of said mirrors b said airspeed responsive means, means for positioning the other of said mirrors by the speed of rotation of said variable speed motor, speed control means for said variable speed motor, a reversible motor op-' erating said speed control means, a control circuit for said reversible motor including said light sensitive element and operated in accordance with the position of the light rays on the light sensitive element to determine the direction of rotation of said reversible motor, the position of said other of said mirrors being varied by variation in the speed of said variable speed motor in response to change in the position of said one of said mirrors by said speed responsive means so as to maintain the light rays at a predetermined point with respect to said light sensitive element, and means responsive to the revolutions of said variable speed motor for recording the air miles traveled.

10. In an air miles recorder for aircraft, means responsive to airspeed, a variable speed motor, an optical follow-up system including a light source, a light sensitive element and an optical system containing means including a pair of mirrors for directing the light rays from said light source upon the light sensitive element, means for positioning one of said mirrors by said airspeed responsive means, means for positioning the other of said mirrors by the speed of rotation of said variable speed motor, means responsive to the position of the light rays relative to the light responsive element for varying the speed of said variable speed motor to move said other of said mirrors to return the light rays to a predetermined point with respect to the light sensitive element after movement of said one of said mirrors, said follow-up being accomplished by movement of the mirrors only while the remainder of the optical system remains stationary, and a counter driven by said variable speed motor for recording the air miles traveled.

11. In an optical follow-up system, an actuated mirror, responsive means for positioning said mirror, a follow-up mirror, a light sensitive element, a light source, the rays from which are reflected from said mirrors to said light sensitive element, a reversible motor means including said light sensitive element by which the direction of rotation of said reversible motor is determined by the energization or de-energization of said light sensitive element by the presence or absence of the light rays thereon, and means for varying the position of said follower mirror in response to the direction of rotation of said reversible motor to return the light rays to said light sensitive element after movement of said actuated mirror.

12. In an optical follow-up system, a light source, a lens for collimatin the light rays from said light source, a first mirror upon which the collimated rays are directed, a second mirror to which the light rays reflected from said first mirror are directed, a second lens for focusing the light rays reflected from said second mirror, a light sensitive element spaced from said second lens by its focal length, the relative position of said mirrors determining the impingement of the light rays upon said light sensitive element, and means controlled by the energization and de-energization of said light sensitive element for effecting movement of one of said mirrors in response to movement of the other of said mirrors.

13. In an optical follow-up system, a light source, a lens for collimating the light rays from said light source, a first mirror upon which the collimated rays are directed, a second mirror to which the light rays reflected from said first mirror are directed, a second lens for focusing the light rays reflected from said second mirror, a light sensitive element spaced from said second lens by its focal length, the relative position of said mirrors determining the impingement of the 8 light rays upon said light sensitive element, one of said mirrors being movable in response to an exterior condition to vary the focal point of said light rays with respect to the light sensitive element, and means responsive to energization and de-energization of the light sensitive element for efiecting movement of the second mirror as a follower to return the focal point of the light rays to its predetermined position with respect to the light sensitive element, said optical follow-up being effected by movement of the mirrors only while the remaining elements of the optical system remain stationary.

JOHN H. ANDRESEN, J R.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,897,850 La Pierre Feb. 14, 1933 1,993,527 Mears et al Mar. 5, 1935 2,216,472 Harrison Oct. 1, 1940 2,269,068 Corbin Jan, 6, 1942 

